LITTLE ROCK (AP) — A Native American tribe that was historically based in Arkansas but now calls Oklahoma home is teaming with descendants of African-American slaves to research and preserve an archaeological site that contains the remains of their ancestors.

The burial sites were discovered on land that the Quapaw Tribe purchased in 2013. The land was part of the Thiboult Plantation near the Little Rock Port Authority. Before that, it was part of the Quapaw's reservation.

John House with the Arkansas Archaeological Survey estimated that the Native American graves at the site date back to 1400 to 1600, while the African-American graves in the same location probably date back from before the Civil War to the early 1900s.

Tribal members met with members of the Preservation of African American Cemeteries recently.